Quite a few devices have been described that offer protections to the soft tissues of the mouth from abrasion by orthodontic braces, but all possess significant drawbacks that have prevented their wide use. One device describes a silicone bracket cap with holes and slits that fit over a bracket and is secured by the main wire, requiring the placement of many caps and a bumpy, irregular feel. Another teaches a silicone shield that employs a room temperature setting silicone that is placed in the mouth and allowed to set. It is then removed from the mouth and trimmed. This is an inconvenient procedure, and sanitary storage must be employed for re-use of the device.
A flat thermoplastic strip has been described that requires heating to between 160-212 degrees Fahrenheit to soften it, whereupon it is pressed and molded onto the teeth and braces. A moldable lip guard has been described that must first be heated in hot water. Another disclosure teaches a two-part curable silicone composition that, upon mixing the parts, yields a putty-like consistency that can be molded over the braces before the cure is complete. The mixing and timing aspects of this device also render it inconvenient to use.
A putty-like, finger-moldable material sold as ORTHOSIL™ Silicone Dental Wax, a product currently on the market, comes in small strips that can be pressed onto the braces to offer protection. ORTHOSIL™ is marketed as a silicon “wax”. This material is not an elastomer, but is rather a thixotropic semisolid that is well known to those practiced in the art of silicones. However, even when molded onto and into the brackets and wires of orthodontic braces, it adheres poorly if the braces are moist with saliva. Unfortunately, braces are typically very moist with saliva since the presence of braces in the mouth commonly stimulates excess saliva production. The saliva acts as a lubricant such that even though molded into and onto the brackets and wires of the braces, the material easily dislodges from the braces. As a result, the instructions for the ORTHOSIL™ Dental Wax product state “Your brackets must be completely dry for Silicone wax to adhere properly.” This is a very difficult state to achieve in the moist environment of a user's mouth without professional assistance, which is not available for day to day usage.
In addition, this material tends to stick more aggressively to the fingers than to the braces if the braces are wet and the fingers are dry, which is typically the case. This causes the silicone wax material to pull off the braces during attempted application. The following Table 1 shows the lateral force exerted by a Mitutoyo Model 546-133 Dial Tension Gauge required to dislodge a pressed-on 0.080 g piece of ORTHOSIL™ from a variety of surfaces (porcelain being used to model the enamel surface of a tooth).
TABLE 1SurfaceForce (milli Newtons)Dry finger tip86mNDry porcelain surface87mNWater-wet porcelain surface<10mN
The force required to dislodge the ORTHOSIL™ from a wet “tooth” is a small fraction of the force required to dislodge it from a dry fingertip, indicating almost no adhesion to the wet “tooth” relative to a dry fingertip.
In addition, it is well known to orthodontists that demineralization (decalcification) of tooth enamel often occurs at the edges of brackets cemented to the teeth due to the presence of plaque, resulting in chalky spots on the tooth surface. Studies have shown that demineralization can occur around orthodontic appliances as early as one month into treatment.